public class AutoAdjustTextview extends TextView{
// Minimum text size for this text view
public static final float MIN_TEXT_SIZE = 20;
// Our ellipse string
private static final String mEllipsis = "...";
// Flag for text and/or size changes to force a resize
private boolean mNeedsResize = false;
// Text size that is set from code. This acts as a starting point for resizing
private float mTextSize;
// Temporary upper bounds on the starting text size
private float mMaxTextSize = 0;
// Lower bounds for text size
private float mMinTextSize = MIN_TEXT_SIZE;
// Text view line spacing multiplier
private float mSpacingMult = 1.0f;
// Text view additional line spacing
private float mSpacingAdd = 0.0f;
// Add ellipsis to text that overflows at the smallest text size
private boolean mAddEllipsis = true;
// Default constructor override
public SizeAdjustingTextView(Context context) {
this(context, null);
}
// Default constructor when inflating from XML file
public SizeAdjustingTextView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
// Default constructor override
public SizeAdjustingTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mTextSize = getTextSize();
}
@Override
protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) {
mNeedsResize = true;
// Since this view may be reused, it is good to reset the text size
resetTextSize();
}
@Override
public void setText(CharSequence text, BufferType type) {
super.setText(text, type);
resizeText();
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
if (w != oldw || h != oldh) {
mNeedsResize = true;
}
}
@Override
public void setTextSize(float size) {
super.setTextSize(size);
mTextSize = getTextSize();
}
@Override
public void setTextSize(int unit, float size) {
super.setTextSize(unit, size);
mTextSize = getTextSize();
}
@Override
public void setLineSpacing(float add, float mult) {
super.setLineSpacing(add, mult);
mSpacingMult = mult;
mSpacingAdd = add;
}
public void setMaxTextSize(float maxTextSize) {
mMaxTextSize = maxTextSize;
requestLayout();
invalidate();
}
public float getMaxTextSize() {
return mMaxTextSize;
}
public void setMinTextSize(float minTextSize) {
mMinTextSize = minTextSize;
requestLayout();
invalidate();
}
public float getMinTextSize() {
return mMinTextSize;
}
public void setAddEllipsis(boolean addEllipsis) {
mAddEllipsis = addEllipsis;
}
public boolean getAddEllipsis() {
return mAddEllipsis;
}
public void resetTextSize() {
if(mTextSize > 0) {
super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize);
mMaxTextSize = mTextSize;
}
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
if(changed || mNeedsResize) {
int widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight();
int heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop();
resizeText(widthLimit, heightLimit);
}
super.onLayout(changed, left, top, right, bottom);
}
public void resizeText() {
int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop();
int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight();
resizeText(widthLimit, heightLimit);
}
public void resizeText(int width, int height) {
CharSequence text = getText();
if(text == null || text.length() == 0 || height <= 0 || width <= 0 || mTextSize == 0) {
return;
}
float newTextSize = findNewTextSize(width, height, text);
changeTextSize(newTextSize);
mNeedsResize = false;
}
private void changeTextSize(float newTextSize) {
setTextSize(TypedValue.COMPLEX_UNIT_PX,newTextSize);
setLineSpacing(mSpacingAdd, mSpacingMult);
}
private float findNewTextSize(int width, int height, CharSequence text) {
TextPaint textPaint = new TextPaint(getPaint());
float targetTextSize = textPaint.getTextSize();
int textHeight = getTextHeight(text, textPaint, width, targetTextSize);
while(textHeight > height && targetTextSize > mMinTextSize) {
targetTextSize = Math.max(targetTextSize - 1, mMinTextSize);
textHeight = getTextHeight(text, textPaint, width, targetTextSize);
}
return targetTextSize;
}
private int getTextHeight(CharSequence source, TextPaint paint, int width, float textSize) {
paint.setTextSize(textSize);
StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
return layout.getHeight();
}
}
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